This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The purpose of this study are to study the influence of ovarian hormones on intracranial pressure (ICP) by a non invasive, MRI based method using a 3T magnet. Our hypothesis is that intracranial pressure is influenced by ovarian hormones, based on our recent findings that women under the age of 50 are at increased risk to develop intracranial hypertension following traumatic brain injury and epidemiologic data that demonstrate that idiopathic intracranial hypertension (also known as pseudotumor cerebri) is 7 times more common in premenopausal women compared with men or older women.